V-doped TiO2 nanobelt array for high-efficiency electrocatalytic nitrite reduction to ammonia

Electrocatalytic nitrite (NO2-) reduction to ammonia (NH3) has been an attractive topic, which not only removes NO2- pollutants existing in surface water and underground water but also synthesizes value-added NH3. Nevertheless, the inactive kinetics for direct six-electron NO2--to-NH3 conversion makes it challenging to explore efficient electrocatalysts for the NO2- reduction reaction (NO2RR). Herein, we report a V-doped TiO2 nanobelt array on a titanium plate (V-TiO2/TP) as a highly efficient NO2RR electrocatalyst. The experimental results and theoretical calculations clarify that V doping can enhance the intrinsic electrical conductivity and effectively optimize the free energy of the TiO2 specialIntscript crystal plane in the potential determining step, resulting in a positive effect on electrochemical NO2RR to NH3. The designed V-TiO2/TP exhibits an outstanding electrochemical NO2RR property with a high NH3 yield of 540.8 mu mol h-1 cm-2 at-0.7 V and an excellent Faradaic efficiency of 93.2% at-0.6 V versus reversible hydrogen electrode, superior to TiO2/TP.

Automated summary

A highly efficient electrocatalyst for NO2 reduction to NH3 was reported in this study, which consisted of V-doped TiO2 nanobelt array on a titanium plate. Both experimental results and theoretical calculations revealed that V doping enhanced the electrical conductivity of the nanobelt and optimized the free energy of the TiO2 specialIntscript crystal plane in the potential determining step, resulting in a positive effect on the electrochemical NO2 reduction to NH3. The designed V-TiO2/TP exhibited outstanding electrochemical NO2 reduction performance with a high NH3 yield of 540.8 μmol h-1 cm-2 at -0.7 V and an excellent Faradaic efficiency of 93.2% at -0.6 V versus reversible hydrogen electrode, surpassing TiO2/TP.